Lifting devices

ABSTRACT

A lifting device comprises a lifting beam formed by two opposed members, for example I or U-section. Self-locking carriages are movable along the beam internally thereof and include lugs engageable with upper and lower flanges of the members. A shaft carried by each carriage is engaged by a beam suspension member or a load supporting hook, and the load applied to the carriage via the shaft urges the lugs into locking engagement with the flanges.

v United States Patent 1 1 1111 3,865,422

Archer Feb. 11, 1975 LIFTING DEVICES 3,314,711 4/1967 Dietz r a1 294/22 R [76] n ento J n a o c A e. 3,343,861 9/1967 Smlclu 294/81 R Georges-Clemenceau, 78670, Vi]] i France Primary Examiner-Robert J. Spar Assistant Examiner-Lawrence .l. Oresky [22] F'ledi May 1974 Attorney, Agent, or FirmEyre, Mann & Lucas [21] Appl. No.: 468,295

[57] ABSTRACT [30] Foreign Application Priority Data I I May lo 973 France 73 743] A lifting device comprlses a lifting beam formed by two opposed members, for example 1 or U-section. [52] Us Cl 294/81 R 294/85 Self-locking carriages are movable along the beam in- [511 In Cl 3 1/00 ternally thereof and include lugs engageable with [58] Fie'ld 67 AA upper and lower flanges of the members. A shaft car- R BB 212/1 ried by each carriage is engaged by a beam suspension member or a load supporting hook, and the load ap- [56] References Cited plied to the carriage via the shaft urges the lugs into UNITED STATES PATENTS locking engagement with the flanges. 2,961,269 11/1960 Renfroe 294/85 5 Claims, 4 Drawing Figures PATEMED FEB] 1 I975 SHEET 1 OF 3 PATENTEB FEB] 1 1975 SHEEI 30F 3 IIIIIIIIIII/ \llll LIFTING DEVICES BACKGROUND OF THE INVENTION 1. Field of the Invention.

The present invention relates to lifting devices.

2. Description of the Prior Art.

Lifting devices have been proposed in the form of a lifting beam with self-locking carriages movable along the beam. Each of these carriages carries an element arranged to be connected to a suspension hook. These carriages are relatively complicated and do not operate very reliably.

SUMMARY OF THE INVENTION According to the present invention, there is provided in a lifting device a-lifting beam, said beam comprising two sectioned members, each said member having an upper flange, a lower flange, and a web, the two members being arranged with their webs in spaced parallel relation, and at least two self-locking carriages movable along the beam between the webs of said members, each carriage including means defining a cavity open to the outside, shaft means engaged in said cavity, and lug means bearing against the upper and lower flanges of the members.

Further according to the present invention, there is provided in a lifting device a lifting beam, said beam comprising two sectioned members, each said member having an upper flange, a lower flange, and a web, the two members being arranged with their webs in spaced parallel relation, at least two self-locking carriages movable along the beam between the webs of said members, each carriage including means defining a cavity, shaft means engaged in said cavity, and lug means bearing against the upper and lower flanges of the members, said shaft means being arranged to carry a load applied by means extending between said members whereby said load urges the lug means into locking engagement with the flanges.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a fragmentary side elevation, partially in section, of a first embodiment of a lifting device in accordance with the present invention;

FIG. 2 is a section taken on line II-II of FIG. 1;

FIG. 3 is a fragmentary side elevation partially in section of a second embodiment of the device; and

FIG. 4 is a fragmentary side elevation of a modified form of the device shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT The lifting device-shown in FIGS. 1 and 2, comprises a lifting beam formed by two generally U-section members 1 and 2 so arranged that their central parts or webs la and 2a are on the outside of the beam; in an alternative arrangement, the Webs la and 2a can be arranged on the inside of the beam. The opposed limbs of a suspension loop 3 extend through openings 4 provided in a flat longitudinal plate 5 which is welded to the underside of the upper flanges lb and 2b of the members 1 and 2. Each of the limbs of the loop 3 is provided at its bottom end with an opening through which a transverse flat plate 7 extends; this plate bears against the underside of the flat plate 5. Because of this arrangement, the flanges lb and 2b are not in contact, and the members 1 and 2 can be spaced by a sufficient distance from one another to permit the use of rotating hooks 8, whilst their webs 1a and 2a remain parallel.

Each of the hooks 8 is rigid with a looped nut 9 which is supported on a shaft 10 carried by a self-locking carriage movable inside the lifting beam. This carriage consists of two plates 11, disposed in the vicinity of the webs 1a and 2a the members 1 and 2, and connected to one another by a transverse member 12. Each of the plates 11 has an opening 13 which receives the shaft 10, and each plate is reinforced by a sectioned member 14 level with the opening 13. As is clearly shown in FIG. 1, each of the plates 11 comprises an upper lug 11a and a lower lug llb, which are spaced by a distance which is greater than the distance separating the upper and lower flanges of the members 1 and 2. When viewed in side elevation, the lower lug 11b is arranged between the upper lug 11a and the opening 13.

It is possible to adjust the effective span of the lifting beam to within one millimetre by displacing the carriages inside the lifting beam. When the beam is in use, the force exerted by the load on the hook 8 tends to cause the plates 11 of the associated carriage to pivot about their lower lugs 11b, which bear against the lower flange of the respective members 1 and 2, whereby their upperv lugs 11a are urged against the upper flange of the respective 1 and 2. The carriage is thus locked or jammed in the lifting beam, and the locking force increases with increasing load.

In the embodiment shown in FIG. 3, the lifting beam is formed from two l-section members. The loop 3 is secured to the lifting beam by means of self-locking carriages which are similar to those described above and which are designated by the reference 15 in FIG. 3. For this purpose each limb of the loop 3 is connected to one of the carriages by a shaft 16 which extends through the holes 13 of the carriage and a hole provided at the bottom of the limb. The carriages 15 do, however, differ from those shown in FIG. 1 in that the upper lugs 15a are arranged between the lower lugs 15b and the holes 13, when viewed in side elevation.

When a lifting hook extends through the loop 3 and a load is attached to the lifting beam, the weight of this load tends to make each of the carriages l5 pivot about the upper lugs 15a and to urge the lower lugs 15b against the lower flanges of the l-section.

When the lifting beam is not carrying a load, the loop 3 can be freely displaced along the beam so as to locate it in a position such that a subsequent load will be balanced.

In the modified arrangement shown in FIG. 4, the loop 3 is replaced by a sling 17 having a loop 18 at each end; each shaft 16 extends through a respective one of the loops 18. When the lifting beam is not loaded it is possible to displace the two carriages 15 or only one of them, thus changing the angle of the two runs of the sling.

In the devices particularly described, the carriages are of relatively simple construction.

What is claimed is:

1. In a lifting device a lifting beam, said beam comprising two sectioned members, each said member having an upper flange,

a lower flange, and

a web, the two members being arranged with their webs in spaced parallel relation, and

at least two self-locking carriages movable along the beam between the webs of said members, each carriage including means defining a cavity open to the outside,

shaft means engaged in said cavity, and

lug means bearing against the upper and lower flanges of the members.

2. A device according to claim 1, wherein each said carriage comprises two plates, and

a transverse member connecting the plates, each plate lying adjacent a web of a respective said member and carrying a first lug bearing against the upper flange of the member, and k a second lug bearing against the lower flange of the member.

3. A device according to claim 2, further comprising lifting hooks, each hook being carried by the shaft means of a respective carriage, in each said carriage the first lugs and the shaft means being arranged at respective sides of the second lugs whereby a load carried by the hook pivots the carriage on the second lugs to urge the first lugs against the upper flanges.

4. A device according to claim 2 further comprising suspension means for suspending the beam, said suspension means being connected to' the shaft means of the carriages, in each said carriage the second lugs and the shaft means being arranged at respective sides of the first lugs whereby the load in said suspension means pivots the carriage on the first lugs to urge the second lugs against the lower flanges,

5. In a lifting device a lifting beam, said beam comprising two sectioned members, each said member having an upper flange,

a lower flange, and

a web, the two members being arranged with their webs in spaced parallel relation,

at least two self-locking carriages movable along the beam between the webs of said members, each carriage including means defining a cavity,

shaft means engaged in said cavity, and

lug means bearing against the upper and lower flanges of the members, said shaft means being arranged to carry a load applied by means extending between said members whereby said load urges the lug means into locking engagement with the flanges. 

1. In a lifting device a lifting beam, said beam comprising two sectioned members, each said member having an upper flange, a lower flange, and a web, the two members being arranged with their webs in spaced parallel relation, and at least two self-locking carriages movable along the beam between the webs of said members, each carriage including means defining a cavity open to the outside, shaft means engaged in said cavity, and lug means bearing against the upper and lower flanges of the members.
 2. A device according to claim 1, wherein each said carriage comprises two plates, and a transverse Member connecting the plates, each plate lying adjacent a web of a respective said member and carrying a first lug bearing against the upper flange of the member, and a second lug bearing against the lower flange of the member.
 3. A device according to claim 2, further comprising lifting hooks, each hook being carried by the shaft means of a respective carriage, in each said carriage the first lugs and the shaft means being arranged at respective sides of the second lugs whereby a load carried by the hook pivots the carriage on the second lugs to urge the first lugs against the upper flanges.
 4. A device according to claim 2 further comprising suspension means for suspending the beam, said suspension means being connected to the shaft means of the carriages, in each said carriage the second lugs and the shaft means being arranged at respective sides of the first lugs whereby the load in said suspension means pivots the carriage on the first lugs to urge the second lugs against the lower flanges.
 5. In a lifting device a lifting beam, said beam comprising two sectioned members, each said member having an upper flange, a lower flange, and a web, the two members being arranged with their webs in spaced parallel relation, at least two self-locking carriages movable along the beam between the webs of said members, each carriage including means defining a cavity, shaft means engaged in said cavity, and lug means bearing against the upper and lower flanges of the members, said shaft means being arranged to carry a load applied by means extending between said members whereby said load urges the lug means into locking engagement with the flanges. 